modpost: do not invoke extra modpost for nsdeps

'make nsdeps' invokes the modpost three times at most; before linking
vmlinux, before building modules, and finally for generating .ns_deps
files. Running the modpost again and again is not efficient.

The last two can be unified. When the -d option is given, the modpost
still does the usual job, and in addition, generates .ns_deps files.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Matthias Maennich <maennich@google.com>

Makefile

@@ -1684,10 +1684,9 @@ tags TAGS cscope gtags: FORCE
 # ---------------------------------------------------------------------------
 
 PHONY += nsdeps
-
+nsdeps: export KBUILD_NSDEPS=1
 nsdeps: modules
-	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost nsdeps
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/nsdeps
 
 # Scripts to check various things for consistency
 # ---------------------------------------------------------------------------

scripts/Makefile.modpost

@@ -53,8 +53,7 @@ MODPOST = scripts/mod/modpost						\
 	$(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS)))	\
 	$(if $(KBUILD_EXTMOD),-o $(modulesymfile))			\
 	$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)			\
-	$(if $(KBUILD_MODPOST_WARN),-w)					\
-	$(if $(filter nsdeps,$(MAKECMDGOALS)),-d)
+	$(if $(KBUILD_MODPOST_WARN),-w)
 
 ifdef MODPOST_VMLINUX
 
@@ -66,7 +65,8 @@ __modpost:
 
 else
 
-MODPOST += $(subst -i,-n,$(filter -i,$(MAKEFLAGS))) -s -T -
+MODPOST += $(subst -i,-n,$(filter -i,$(MAKEFLAGS))) -s -T - \
+	$(if $(KBUILD_NSDEPS),-d)
 
 ifeq ($(KBUILD_EXTMOD),)
 MODPOST += $(wildcard vmlinux)
@@ -96,8 +96,6 @@ ifneq ($(KBUILD_MODPOST_NOFINAL),1)
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
 endif
 
-nsdeps: __modpost
-
 endif
 
 .PHONY: $(PHONY)

scripts/mod/modpost.c

@@ -2221,8 +2221,7 @@ static int check_exports(struct module *mod)
 			add_namespace(&mod->required_namespaces,
 				      exp->namespace);
 
-			if (!write_namespace_deps &&
-			    !module_imports_namespace(mod, exp->namespace)) {
+			if (!module_imports_namespace(mod, exp->namespace)) {
 				warn("module %s uses symbol %s from namespace %s, but does not import it.\n",
 				     basename, exp->name, exp->namespace);
 			}
@@ -2642,8 +2641,6 @@ int main(int argc, char **argv)
 
 		err |= check_modname_len(mod);
 		err |= check_exports(mod);
-		if (write_namespace_deps)
-			continue;
 
 		add_header(&buf, mod);
 		add_intree_flag(&buf, !external_module);
@@ -2658,10 +2655,8 @@ int main(int argc, char **argv)
 		write_if_changed(&buf, fname);
 	}
 
-	if (write_namespace_deps) {
+	if (write_namespace_deps)
 		write_namespace_deps_files();
-		return 0;
-	}
 
 	if (dump_write)
 		write_dump(dump_write);